There is much debate around top dressing succulent pot arrangements and garden beds. I have seen it all, mulching with sugar cane, mulching with bark and the most preferred method used by experienced growers – rocks and non organic matter. It really does matter what top dressing you use. Any organic matter will break down, retain too much moisture and potentially rot your beautiful succulents. Scoria stone is the best, it contains little air holes which allows your pots to drain easily and won’t blow away… it also helps keep your creations weed free!
If your pots or garden beds are ever pest or disease infested it is best to remove your succulents and treat them especially if it is mealy bug, they can be found hiding in the plants root system and if not treated can continue to cause issues for your succulents. Remove the infected plants from the soil and wash well using a hose, then treat with your preferred method (do not use white oil).
Removing all soil surrounding the infested area and rock is important as the critters could also have found their way into the soil. Dispose of the old soil and wash your rocks thoroughly. Repot or plant into fresh soil once your succulent has been thoroughly treated. Image above shows a fresh top dressing of scoria stone.